8 cylinder front engine iconic vehicle
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By Sazerac
#303211
Hi All

So right before putting the 91 away for the winter, I changed out the rear brake rotors. The problem was that I had changed the pads a couple years back, but the worn slots in the rotor were slightly to small for the new pads and the brakes were generally grinding quite loudly. (Not that brake squeal bothers me, but this was really too much.)

Anyway that went all ok and all squel is gone, but I found the emergency brake pad to be quite literally destroyed. I guess this is just age. Do people do anything about this or just leave it? Hell, are parts even available?
RearEmergencyBreak.jpg
Many thanks in advance for any thoughts, comments...

John
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By worf
#303214
Several things:

1) did you follow the WSM procedure to "back off" the e-brake shoes before you removed the rear discs? Were they hard to got off? Did you need to use a BFH? Are both sides f'd up like the picture?
2) check your email
3) I have never seen 928 e-brake shoes that bad at any age. Something was going on in there. Are any springs broken? Were the rear brakes not releasing? Did the e-brake lever feel too tight?
4) Do not order new e-brake shoes. Order used ones from Mark. New ones are 997 parts and - per PET - require several new related parts.
5) You should look into who last serviced those brakes and discuss it with them.
Last edited by worf on Tue Apr 01, 2025 11:23 am, edited 1 time in total.
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By Sazerac
#303217
Gee.. Wow, thanks for such quick answers. No, I did not back of the e-brake as per WSM. Noted for the future. But the discs came off without a problem or any force at all really. Also, effectively the ebrake works like it did before. The material was just totally crumbly. Maybe it is a past damage or something.

I'll check with Mark for replacements in good shape then. I guess a truck shop would work, but then I would have to wait with the car disassembled.

Many thanks for the input. It looked quite strange to me too.
By worf
#303220
Take many before pictures. And look at the WSM. This is not a totally obvious job once all the pieces are on the floor. Getting the springs released can be interesting. Not as interesting though, as getting it all reassembled and working with the wheel hub in place. Before you release the springs note how they are retained, especially the "middle" one for each shoe. Do this by looking for the "hook" on the inboard side of the rear wheel carrier.

There are a lot of moving parts some of which can fall out and roll far across the floor once it all comes loose.

Last, review the WSM on adjusting the e-brake after reassembly. Do this - WSM consultation- before and after you put the disc on.
By smiffypr
#303230
The problem is that the steel rusts then the friction material comes away with the flaking rust.
New shoes are easily available in the UK from a general motor factor, (check ebay) the only issue is that the steel is now plated but they hadn't taken the thickness of the plating into account, so the slots that the shoe engages in needs to be widened slightly.

Smiffy
By worf
#303234
smiffypr wrote: Sun Mar 30, 2025 7:37 pm The problem is that the steel rusts then the friction material comes away with the flaking rust.
Rust is 10x the problem in the UK as it is in the Northeast US.

And 100x the problem compared to the Los Angeles area where Mark's warehouse is located.

Used replacements from Mark should be virtually rust free (and are, in my experience.)

Ok, a very thin layer of surface rust. But very much unlike the barnacle-encrusted bits that Paul posts picture of.
By WyattsRide
#303261
worf wrote: Sun Mar 30, 2025 5:49 pm Several things:

1) did you follow the WSM procedure to "back off" the e-brake shoes before you removed the rear discs? Were they hard to got off? Did you need to use a BFH? Are both sides f'd up like the picture?
This is a very important step in removing the Rotors. I didn't realize that I didn't do this until after spending over an hour banging the Rotor loose! I needed that BFH! (or do what the WSM says and spend 2 mins like I did on the second side!)


worf wrote: Sun Mar 30, 2025 6:19 pm Take many before pictures. And look at the WSM. This is not a totally obvious job once all the pieces are on the floor. Getting the springs released can be interesting. Not as interesting though, as getting it all reassembled and working with the wheel hub in place. Before you release the springs note how they are retained, especially the "middle" one for each shoe. Do this by looking for the "hook" on the inboard side of the rear wheel carrier.

There are a lot of moving parts some of which can fall out and roll far across the floor once it all comes loose.

Last, review the WSM on adjusting the e-brake after reassembly. Do this - WSM consultation- before and after you put the disc on.
Funny how I read this after spending the afternoon trying to figure out why the top middle spring and top shoe were loose and not tight against wheel carrier on the rear left side (see why in above response). With all the banging and shaking that I did, that spring must have turned and got unhooked from the back side. I initially thought it was broken. Using a mirror, showed how the others were hooked. It was a little tricky getting that spring compressed then rehooked in the back. But, I finally got it. Wish I would have taken some pics to clarify.

It truly amazes me what guys like Dave (Worf) already know as general knowledge about these cars.
By worf
#303262
WyattsRide wrote: Mon Mar 31, 2025 10:40 am It truly amazes me what guys like Dave (Worf) already know as general knowledge about these cars.
I have screwed up every task at least once. Thus I have knowledge.

However, in the vast majority of cases I figure it out before delivery back to the client.
By worf
#303263
That reminds me:

https://www.summitracing.com/parts/wmr-w86557

https://www.summitracing.com/parts/wmr-w175

A buck cheaper on AMZN but those URLs don't work here, so fuck Amazon.
By Sazerac
#303313
WyattsRide wrote: Mon Mar 31, 2025 10:40 am This is a very important step in removing the Rotors. I didn't realize that I didn't do this until after spending over an hour banging the Rotor loose! I needed that BFH! (or do what the WSM says and spend 2 mins like I did on the second side!)
Ok, so just to clarify this I did not need to bang on the rotors really. A little back and forth motion and they came right off. In the future of course I will back the ebrake shoes off as per the WSM. Also, no debris was really generated, so I don't really think I destroyed them taking them off. I would have seen that much debris given how much is missing.

Anyway, the path is clear. Buy used ones from Mark, replace carefully following the WSM and take lots of pictures!
By Crumpler
#303503
What’s ironic is that I just deleted the e-brake system on the track car. Not necessarily for weight or anything else. I just didn’t want to re-assemble the stupid gaggle of finicky springs and levers.
Good news: still street legal somehow in Missouri.
By Sazerac
#311683
Haven't really made much progress here, but did get the brake shoes from Mark. In my opinion impeccable... No rust really at all just some surface dirt.
https://shop.928intl.com/Used-Hand-Brak ... D097%2D10/
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By XR4Tim
#311827
I imagine there are plenty of automatic 928s that had the e-brake used only once or twice in their whole existence, so the supply of used ones should last a long time.
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